Standard light bulbs are designed to be inserted into complementary light sockets and operate off an electrical grid of a house, building, school, hospital or emergency center. Generally, such a light bulb is merely installed into a socket, used when a light switch is turned on, then turned off with the switch, and not thought of until it goes dead and needs to be replaced. In an emergency situation, such as during a power outage, such standard light bulbs do not work; if there is no power to the electrical grid, then there is no power to the light bulb. People will resort to temporary, portable light sources, such as flashlights and candles, but such light sources may not sufficiently light a room. A building may have an emergency power source, such as a generator, which will provide the ability to keep a room lit, but in severe emergency situations with a power outage that might not be fixed for a while, the user typically must try to optimize use of the generator and selectively use the back-up power to operate necessary devices within the home. As a result, the user typically will not use up the generator power on lighting throughout the building, and opt, instead, to rely on flashlights and candles. More industrial buildings, schools, hospitals and emergency centers, will have dedicated emergency lighting operating off a generator, but residential buildings often do not have such emergency back-up systems in place.
Another issue with standard light bulbs is that they often have just one operational mode. That is, they simply operate at a constant wattage until they stop working. If the light bulb is hooked into an emergency power system, it will use up power so long as the light is on, even if there is sufficient ambient light to help the user without needing any lights on in a room or building. In general, much energy is wasted by keeping lights on—especially emergency lights—longer than necessary. Additionally, much energy is wasted by using light bulbs, even in normal non-emergency usage, at full intensity, whereby adjusting such intensity, even slightly based on alternative light sources, could preserve some power.
In view of the foregoing, there is a need for a light bulb that can be used as a normal light bulb—that is, inserted into a standard light socket to be powered off of an electrical grid—but also available for use during a power outage to provide safety lighting. Additionally, there is a need for such a light bulb that is portable and useable even when it is not inserted into a light socket, or even when removed from a light socket, such as in an emergency situation. That is, there is a need for a light bulb that utilizes battery power and can therefore be used as a portable flashlight as a functionality in addition to its normal use as a standard light bulb. Further, there is a need for a method of operation of such a light bulb so as to preserve the battery power, both in normal use and in emergency use. Accordingly, there is a need for a battery-operated light bulb having a built-in timer that can control the amount of time the light bulb is on, and/or a sensor system that can determine and adjust as necessary the intensity of light needed for an emergency situation, including if the light bulb even needs to be on if sufficient ambient light is available. Still further, there is a need for a light bulb that can turn on automatically given a power outage, a sensed low level of ambient light, or operate as safety lighting based on motion sensed in the room in which the light bulb is installed. Accordingly, it is a general object of the present invention to provide a portable charger that improves upon conventional light bulbs currently on the market and that overcomes the problems and drawbacks associated with such prior art light bulbs.